A glucose-regulated protein, GRP58, is down-regulated in C57B6 mouse liver after diethylhexyl phthalate exposure.
Diethylhexyl phthalate (DEHP) is a widely used plasticizer that induces peroxisome proliferation in rodents. Prolonged exposure to DEHP results in a variety of toxic effects, the most significant of which appears to be an increased incidence of liver cancer and male reproductive toxicity in rodents. Accompanying these toxic effects is the induction of a number of genes within the liver, particularly those genes involved in peroxisomal fatty acid beta-oxidation and members of the cytochrome P450 family, CYP4A. In order to explore which additional genes may be altered by DEHP exposure, mRNA differential display was performed using total liver RNA from male C57B6 mice that were treated with either O or 2% DEHP in their diet for 7 days. In doing so, a number of partial cDNAs representing messages that are potentially differentially expressed have been isolated. One of these cDNAs was found to be similar to the previously cloned gene, GRP58. Analysis by RNase protection assay and North hybridization have shown that the transcript for GRP58 is down-regulated in the liver after DEHP exposure. Analysis of dose-response exposures to DEHP by reverse transcription (RT)-PCR confirm these results and also shows that GRP58 is not altered in kidney or testis. Immunoblot analysis using GRP58-specific antibodies also shows a decrease in GRP58 protein levels in DEHP-treated mice. Moreover, exposure of mice to another peroxisome proliferator, clofibrate, results in a slight down-regulation of GRP58 at the highest dose, 0.5%. Thus, it appears as if DEHP and clofibrate can use different pathways to affect gene expression.
Muhlenkamp
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Department of Entomology, University of California, Riverside 92521, USA.
Gill
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D000818:Animals; D001483:Base Sequence; D001835:Body Weight / Q000187:drug effects; D002994:Clofibrate / Q000633:toxicity; D017931:DNA Primers / Q000737:chemistry; D018076:DNA, Complementary / Q000032:analysis / Q000187:drug effects; D004051:Diethylhexyl Phthalate / Q000633:toxicity*; D004305:Dose-Response Relationship, Drug; D015536:Down-Regulation; D004721:Endoplasmic Reticulum / Q000378:metabolism*; D015972:Gene Expression Regulation, Neoplastic; D006360:Heat-Shock Proteins / Q000378:metabolism*; D007535:Isomerases / Q000378:metabolism*; D008099:Liver / Q000187:drug effects* / Q000378:metabolism; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008969:Molecular Sequence Data; D009929:Organ Size / Q000187:drug effects; D016133:Polymerase Chain Reaction; D019704:Protein Disulfide-Isomerases; D012333:RNA, Messenger / Q000378:metabolism; D017422:Sequence Analysis, DNA
D017931:DNA Primers; D018076:DNA, Complementary; D006360:Heat-Shock Proteins; D012333:RNA, Messenger; D004051:Diethylhexyl Phthalate; D007535:Isomerases; C513195:Pdia3 protein, mouse; D019704:Protein Disulfide-Isomerases; D002994:Clofibrate